Electromagnetic mercury relay



June 21, 1949. J. P. KEATING 2,474,000

ELECTROHAGNETIC MERCURY RELAY Filed April 6, 1946 3 Sheets-Sheet 1 Jnz/erz orf June 21, 1949. J. P. KEATING ELEGTROMAGNETIC MERCURY RELAY 3 Sheets-Sheet 2 Filed April 6, 1946 Jue 2l, 1949. J. P. Kl-:ATING 2,474,000

BLBCTROMAGNETIC MERCUR)v RELAY Filed April 6, 1946 5 Sheets-Sheet 3 o, mus QR Patentedlune 21, 17949..

ELECTROMAGNETIC MERCURY RELAY John l.l Keating, Elkhart, Ind., assigner to Durakool, Inc., Elkhart, Ind., `a corporation of Indiana Application April s, 194s, serial No. 660,031

Claims. (Cl. 200-112) My present invention relates toan improvement in relays, and more particularly to mercury to mercury contact type of relays.

In the several embodiments of my invention herein disclosed lI have shown and described mercury relays of the normally open type comprising a m'etal casing or shell which is adapted to serve as one electrode or terminal for the relay, and in which an electrode means is mounted in insulated relation and serving as a second electrode for the relay. The casing or shell provides for the support of a main body of mercury and a plunger means is containedvyvithin` the casing or shell with the plunger means being adapted to be normally supported in floating relation in the main body of mercury. The plunger means is of a character to provide for'the support of asecond body of mercury in contacting engagement with the aforesaid electrode means and normally in insulated relationwith respect to the main body of mercury in the casing or shell sothat in the normal position of the plunger means the circuit through the relay is open. Upon energiration of the coil of the relay the plunger means is attracted, and in its attracted position displaces the body of mercury in the shell or casing to effect contacting thereof with the second body of mercury of the plunger means to provide a mercury to mercury contact in effecting completing of a circuit between the casing or shell and the electrode means associated therewith. As will appear from the detailed description of the several embodiments of my invention I have provided several rforms of plunger means for providing relays of the aforesaid normally open type and which plungers are of a character to provide a rst relay of quick-make Aand quickbreak type, a second relay of slow-make and slowbreak type, and a third relay of quick-make and slow-break type. It will be understood that while my invention has particular utility for use in a relay of the metal casing or shell type, it will be understood that the casing or shell may be made of insulating material in which an electrode member is suitably mounted for contacting engagement with the main body of mercury in such n, casing or shell, and which together with the sfcresaid electrode means provides a pair of electrodes or terminals for the relays.

It is an object of my invention to provide a mercury to mercury contact type relay comprising a pair of electrode means arranged in insuthe relay, and the other of the electrode means having contacting engagement with a second body of mercury supported in a displacer or plunger means normally disposed in iloating relation in the main body of mercury, and which plunger means in its normal position insulates the main and second bodies of mercury from each other.

In a relay constructed, as last referred to, ens ergization of the coil thereof will be effective to attract the displacer or plunger means drawing it downwardly into the main body of mercury in the casing or shell and which movement of the displacer or plunger meansis eiective to displace the main body of mercury into contacting engagement with the body of mercury supported by the plunger or displacer means. Preferably, the plunger means is constructed to provide for support of the second body of mercury in a manner to eiect submerging of the same in the, main body of mercury upon energization of the coil to assure that the mercury supporting means of the plunger is charged with mercury each time the coil is energized. i

A further object of my invention is to provide a mercury to mercury contact relay as aforesaid having plunger means of a character to provide quick-make and quick-break of a circuit through the relay.

A further object of my invention is to provide a mercury to mercury contact relay having plunger means of a character to provide slowmake and slow-break of a circuit through the relay.

A still further object of my invention is to provide a mercury to mercury contact relay having plunger means of a character to provide quickmake and slow-break of a circuit through the relay. y

A further object of my invention is to provide a novel form of plunger ,means for effecting operation of a relay of a character adapted to float normally i-n a main body o'f mercury for the relay, and having a means for supporting a second body of mercury normally in insulated relation with respect to the main body of mercury and in contact with one of a pair of electrode means for the relay.V

A further object of my invention is to provide a plunger means as last aforesaid of a character to effect quick-make and quick-break of a circuit through the relay.

A further object-is to provide a plunger means of the character noted to provide for slow-make and slow-break of a circuit through the relay.

`be turned or spun A further object is to provide a`plunger means of the character noted operable to effect quickmake and slow-break of a circuit through the relay. l

The above andother objects andxadvantages of my invention will appear from the detailed description. g

Now, in order toacquaint those skilled in the art with the manner of constructing and utilizing relays in accordance with my present invention, I shall' describe in connection with the accompanying drawings certain preferred embodiments of my invention.

In the drawings:

Figure 1 is a detail vertical sectional view through one form of relay constructed in accordance with the principles of my present invention.

showing it in its closed position;

Figure 5 is a detail vertical sectional view of.

still another embodiment of a relay constructed in accordance with my invention with the relay being shown in its normally open position; and Figure 6 is a view of the relay of Figure 5 showing it in its closed position. ,f

Referring now to Figures 1 and 2, I have shown a relay 3 comprising a metal casing or shell 4 formed by a cylindrical tube of stainless steel or other suitable metal having a closed lower end wall 5. 'I'he casing 4 is commonly referred to in the art as an open envelope type of casing and in the several embodiments o! my invention herein disclosed serves as one electrode or terminal for the relay. An electrode 6 serving as a second electrode or terminal for the relay extends inwardly of the open upper end of the casing 4 and is suitably mounted in insulated and preferably gas-tight relation thereto. The electrode 6 may be oi' any suitable form and, as shown, it is embedded in a glass bead 9 which in turn is carried in and fused to the inner surface of a metal sleeve I I. 'I'heelectrode 8, the glass bead 9 and the `sleeve Il are first assembled' into a unit before being mounted in the open end of lche tube 4. The sleeve II at its lower end is provided with a radially outwardly extending flange I2, which flange is adapted to seat upon an annular steel washer or stop member I3, and which in turn seats upon an annular shoulder I4 preferably formed by the intersection of the enlarged counterbore at the open endof the casing withl the smaller normal boreA I5 oi! the tube. In assembling the relay, the steel washer I3, together with the unit formed by the electrode 8, the glass bead 9, and sleeve Il are caused to occupy the position shown in Figure 1 after which an annular resilient gasket I6 of rubber or other suitable material is positioned over the sleeve I'I and seated upon the flange I2 thereof. 'I'he annular gasket IB has an internal diameter equal to or slightly greater than the sleeve I l for iltting over the latter. ring I1 may then be positioned `on top of the resilient gasket I6. With the parts in the position described the open end of the casing 4 may inwardly to secure the annuposition shown. This turnend of the casing serves to lar ring I1, in the ing in of the open If -desired an annular metal compress theannular gasket between the flange I2 of sleeve II and the annular member I1 to form a seal at the adjacent innercylindrical surface of the casing. In the form of relay herein disclosed this seal is not depended upon to form a gas-tight seal, but rather serves principally to prevent mercury lfrom escaping from internally of the casing. However, if desired the. annular metal ring l1 may be dispensed with in which case the turned in end of the casing could be caused to engage the resilient gasket I 8 to form both a gas-tight and liquidtight seal. When the mounting means includes the annular member Il a gas-tight seal may be formed between the turned in end of the tube, the metal ring I1, and the sleeve Il by an annular ring of solder I8 which extends from the outer periphery of the casing or tube to the sleeve the As lead I9, as shown, is adapted to be secured to the switch casing by means of the ring of solder -I to provide one lead for the switch. Also, a second lead 2li, as shown, is secured as by soldering to the outer end of the electrode 6. The mounting of the electrode 8, as above described, -of itself forms no part of my present invention and is more fully disclosed and claimed in the co-pending application of Herbert E. Bucklen III, Serial No. 647,867, filed February 15, 1946, now Patent No. 2,450,780, granted October 5, 1948, to which reference may be had. It will be understood that this is but one form of mounting means suitable for use in practicing my present invention and that this mounting means may vary widely in form. The electrode member 6, the glass bead 8 and the sleeve Il are preferably madey of materials having substantially matching thermal coemcients of expansion to prevent breaking away of these parts from each other due to heat generated in operation of the relay. Glasses and metals having such characteristics are now well known in the art with one such metal consisting of approximately 25% nickel, 17% cobalt, 0.3% manganese and the balance of iron. Likewise suitable borosilicate 7 glasses, otherwise known as hard glasses, are suitable for use with the metal parts made of the aforesaid alloy. l,

The closed end. 5 of casing 4, as is also known, is provided with a suitable tubulation 21 of known form and serves for evacuating the casing and filling the same with mercury. After the unit has been assembled, as described, it may be inserted in a cylindrical shell or enclosing housing 22 formed of any suitable insulating material. The open ends of the tube 22 are then nlled with suitable plastic sealing composition 24 to seal the metal relay casing in the housing 22. It will be observed that the leads I9 and 20 are embedded inthe plastic sealing composition adjacent the upper end of the relay and this sealing composition is preferably of a character providing a fluid-tight seal between the several elements assembled within the open end of the casing 4 and theY enclosing housing 22. This arrangement of a metal casing in a housing of lnsulating material of itself forms no part of my presentinvention and is further described in detail in the above referred to application of Herbert E. Bucklen III.

The relay 3 further comprises an energizing coil 25 carried in a suitable supporting bracket lof cylindrical shape and of suitable dimensions for receiving asubstantially cylindrical plunger or displacer means 33. The dlsplacer means 33 comprises a substantially cylindrical metal sleeve' f inwardly turned in ,upper edge 35 of the sleeve member 3| into engagement with a conical shoulder 36 formed between the intersection of the reduced upper cylindrical end 31 of theVmember 32 with the main body portion thereof secures the metal sleeve member 3| and the insulating member 32- in assembled relation. As shown the member. 32 is provided with a bore 33 extending closed end portion 39 thereof closing the lower end of the metal sleeve member 3|. The plunger 33 constructed as described has normal floating relation in a main or first body of mercury 4| 4 and a second body of mercury 42 is contained or supported in the bore 33 of the ceramic member 32 with the plunger means 33 in its normal floating position effecting engagement of the inner end portion of the electrode 5 with the body of mercury 42 contained within the bore 33 of the plunger means 33. It will be observed in the position of the plunger means 33 as shown in Figure 1 and with the coil means 25 de-energized that the relay is in normally open position.

Referring now to Figure 2 the plunger means 33 is shown in the position in which it is caused to be attracted upon energization of the coil 25 and in which position the plunger means 33 is caused to be submerged in the main body ofmercury 4|. The plunger means in this position displaces the latter body of mercury so that it is adapted to have contacting engagement with the body of mercury contained in bore 33 through the open top of the plunger means 33 completing a circuit between the electrode 5 and the casing 4 of the relay. Upon de-energization of the coil means 25 the plunger returns to its normal floating position of Figure 1, and the circuit is caused to be broken by separation of the first and second bodies of mercury from each other by the shearing action of the upper peripheral edge 44 of the ceramic cup-shaped member 32.

As shown the lower end of the ceramic insulating member 32 is preferably rounded so that when the plunger is in its attracted position as shown in Figure 2 the main body of mercury 4| will be disposed therebetween and the closed end 5 of the casing 4 so that upon de-energization of the coil means 25 the plunger will not tend to adhere or stick in its attracted position.

The outer cylindrical surface of metal sleeve V3| is of a diameter slightly less than the diameter of the internal cylindrical surface of the shell or casing 4 and the sleeve 3|, as shown, carries onits outer cylindrical surface a plurality of ball elements 3 I" which have guiding engagement with the internal cylindrical surface of the shell or casing 4 in the vertical movement of plunger 33. The relative diameters of the sleeve 3| of the plunger and the internal cylindrical surface of the shell provide for preventing cooking or binding of the-plunger in its movement in the shell. The incorporation of a guide means such as the ball elements 3|' serves to provide for centering the 2 contained in the lower end portion of the casing l 6"' 'plunger and guiding it in its' movement in the shell, and suchv ball elements are further described and claimed in the application of Herbert E. Bucklen III, and 'Glen L. Weimer, Serial No. 663,368, -flled April 19, 1947,` now abandoned. However, any other suitable known form ot guide means may be used if desired. Also, it will be observed xthat the electrode is of a diameter relative tothe diameter of bore 33 in ceramic insulator 32 so that inthe transverse or lateral movement of the plunger in the shell the electrode 3 doesy vnot contactv the surface defining the bore 33 so a's to prevent any binding of the plunger on'this score.

It will be observed that the relay shown in Figures 1 and 2 is of the mercury to mercury contact type having a normally open position and which provides upon the energization and deenergization of the coil means quick-make and H0 quick-break of a circuit through the'relay 3. inwardly from the upper end thereof with the Referring now to Figures 3 and 4 I have shown another relay 53 constructed in accordance with my invention inwhich the construction. of lthe relay 53 is identical to-the construction of the relay described in connection with Figures I and 2 except for the plunger means 5| thereof. The parts of the relay of Figures 3 and 4 bearing reference numerals 4 through 21 are identical with the parts of the. relay of Figures 1 and 2 above described.

The plunger means 5| of the embodiment of my invention shown in Figures 3 and 4 comprises a.

substantially cylindrical metal sleeve 52 having a reduced upper cylindrical extension 53. A cupshaped member 54 of insulating material likewise constructed of the known ceramic materials presently used in the construction of mercury switches and relays comprises an enlarged cylindrical end portion 55 disposed within the lower 4U end of the cylindrical member 52 and adapted to be secured therein between an annular shoulder 55 formed adjacent the lower end of the cylindrical member 52 and the turned in outer edge 51 of the lower end of the latter. The member 4,-, 54 is provided with an integral cylindrical extending portion 58 having a bore 53 extending inwardly from the upper end thereof with the cylindrical extension 53 being disposed Within the cylindrical sleeve 52 and spaced therefrom to pro- 50 vide an annular recess 53 between the inner cylindrical surface of the member 52 and the cylindrical extension 53 of the insulating member 54. In this form of the invention the wall of the cylindrical portion 52 is provided with a meter- 5.3 ing port or orifice 52 opening into the lower end of the annular recess 63. The plunger` means 5| of this form of my invention by virtue of the previously described construction thereof is adapted to have normal oating relation in the 60 body of mercury 64 supported in the lower end of the casing 4, and the bore 53 is adapted to 'support a second body of mercury 65 in engagement with the inner adjacent end of the electrode 6 in the normal position of the relay. In

the normal position of the relay it will be observed that the second body of mercury 59 is out of contact with the first body of mercury 54 so that when the coil 25 is de-energized the relay is in open position. Referring now to Figure 4 I have shown the position the plunger means 5| occupies when the coil 25 of the relay is energized. Upon energization of te coil means 25 the plunger means 5| is immediately drawn to its attracted position to displace the body of mercury 34 in the casing 4. However the sleeve member 52 tohas more specifically 7 gether with the reduced cylindrical extension 53 thereof is of sumcient length to prevent mercury from spilling over the open upper end` thereof which necessitates the mercury passing through the metering orifice l2 gradually filling the annular Vrecess 50 and thereafter coming into contacting engagement with the body of mercury contained within the bore 59 of the cylindrical portion 58 of the cup-shaped member 54. When this occurs a circuit is completed between the electrode 6 and the casing 4 of the relay. It will be understood that the one or more metering orifices 62 may be provided for effecting'a time delay after energization of the coil 25 before the body of mercury in the lower end of the casing 4 is adapted to have contacting engagement with the body of mercury in the -bore 59 of the cupshaped member 54. Now when the coil 25 is de-energized the plunger means 50 will return to the position shown in Figure 3 of the drawing -but the return of the plunger means to this position will not effect the immediate breaking of the circuit between the pair of bodies of mercury. 'I'he metering orifice .62 effects a time delay in the passage of mercury out of the annular recess 50 and which when the mercury drops below the upper open end of the cylindrical extension Il of the member 54 effects opening of a circuit through the relay.

Also, preferably, the lower end of the member 54 is rounded as at 66 to prevent adhering of the plunger in its attracted position upon deenergization of the coil means 25 which feature been referred (to in connection with the embodiment of our invention described in connection with Figures l and 2.

52 of this embodiment of my tion noted effects closing of the lower end of the and the inner cylindrical surface of the sleeve member 1I. The cylindrical extension 16 is provided with a. co-axially extending bore 18 which is. adapted to receive and support a body of mercury 19. As before, the metal sleeve member 1I is provided with one or more metering ports 80 opening into the annular recess 1l adiacent the lower end thereof. The plunger means 10 with the coil 25 of the relay de-energized is adapted to be supported in floating relation in the main body of mercury ll2 lcontained in the lower end portion of the relay casing 4.

In the position of the plunger means 'l0 as shown in Figure 5 the coil means is de-energized and'it will be observed that the main body of mercury 82 in the relay casing 4 and the body of mercury 19 in 'the .bore 18 of the cup-shaped member 12 are out of contact so that the circuit through the relay is open.

Referring now to Figurev 6 the plunger means 'I0 is shown in the position it is caused to be assumed upon energization of the coil means 25. and it will be observed that the plunger l in its attracted position is effective to displace the main body of mercury 82 to be submerged therein /whereupon the Amain body of mercury overflows the upper open end of the metal sleeve 'H to provide quick-make of a circuit between the electrode member 8 and the casing 4 of the relay. Now, upon de-energization of the coil means 25 it will be observed that the circuit between the electrode 8 and the casing 4 will not be opened or broken until the mercury in the annular re cess ll has metered through the metering orifice 80 in an amount to effect disengagement of the main body of mercury with the body of mercury 7 The member l2 is provided with a cylindrical portion 16 extending co-axially of the metal sleeve sleeve member 'H and spaced therefrom to provide an annular recessll between the outer cylindrical surface of the cylindrical portion 1B in the bore "I8 below the open edge of the cylindrlcal portion 1B so that a time delay is provided before opening of the circuit through the relay upon de-energizatlon of the coil means 25, It is to be observed that the plunger means l0 of the embodiment of the invention of Figures 5 and 6 is substantially identical to the plunger means described in connection with the embodiment of my invention shown in Figures 3 and 4 except that the latter is provided with the reduced cylindrical extension 53 which is effective to prevent the spilling of mercury through the open upper end of the latter sleeve member upon ener'- gization oi' the coil means 25. However, by eliminating the cylindrical extension 53 and forming the main cylindrical body member ll of the plunger means 10 of the proper length with respect to the amount of mercury disposed in the lower end of the casing 4 quick making of 9, circuit through the relay may be effected upon energization of the coil rather than the slow making of the circuit as in the relay of Figures 3 and-1.

.As described in connection with the embodiments of my invention shown in Figures 1 through 4, the relay shown in Figures 5 and 6 has the plunger 10 thereof formed of avdiameter slightly less than the internal diameter of the shell or casing -4 with the electrode 6 and the bore 18 being of appropriate diameters to prevent engagement of the electrode 6 with the surface defining the bore 'I8 in the limited lateral movement of the plunger in the shell or casing 4 as permitted by the differences in diameters between the external cylindrical surface of the plunger and the internal cylindrical surface of the casing or shell 4.

While I have shown and described mercury relaysof the metal casing type it is believed that it will be obvious that mercury relays having a casing or shell made of any suitable insulating material and having an electrode member extending thereinto adapted to have continuous contacting engagement with the main body of mercury in the lower end of the casing may be substituted for the casing member l of the several relays above described. 'Ihe operation of such relays would be the same as that of the relays described in that the plunger member would serve to establish a circuit between the electrodes when energized and to break the circuit when deenergized. In other words it will be clear that in lieu of the metal casing serving as an electrode a casing of insulating material provided with a suitable electrode having contacting engagement with a body of mercury in the casing could be utilised without departing from my present invention.

While I have shown what I consider to be the preferred embodiments of my invention it will be understood that various modifications and rearrangements may be made therein without departing from the spirit and scope of my invention.

I claim:

l.y A mercury relay comprising a pair of electrode means insulated from each other with one of said electrode means having contacting engagement with a first body of mercury for said relay, plunger means open at the upp l end thereof adapted to be normally suppor in floating relation in said first body of mercury for supporting a second body of mercury in insulated relation with respect to said rst body of mercury and in contacting engagement with the other of said electrode means, coil means adapted when energized to attract said plunger means to submerge the latter in said iirst body of mercury and thereby eiect lengagement thereof with said second body of mercury through the open upper end of said plunger means providing quick making of a circuit between said pair of electrode means, and said plunger means having metering means between said bodies of mercury through which mercury withinv said plunger means is returned to said rst body of mercury for effecting a time delay in disengaging of said first body of mercury from said second body of mercury upon de-energization of said coil means and with said plunger means in its normal position.

2. A mercury relay comprising a pair of electrode means insulated from each other with one of said electrode means having contacting engagement with a first body of mercury for said relay, plunger means adapted to be normally supported in oating relation in said first body of mercury for supporting a second body of mercury in insulated relatir'm with respect to said first bodyl of mercury and in contacting engagement with the other of said electrode means, coil means adapted when energized to attract said plunger means to draw the latter into said iirst body of mercury and displace the same into contacting engagement with said second body of mercury to complete a circuit between said pair of electrode means, and said plunger means having metering means between said bodies of mercury for effecting a time delay in the contacting of said first body of mercury upon displacement of the same with said second body of mercury upon energization of said coil means and with said plunger means in its attracted position.

3. A mercury relay comprising a pair of electrode means insulated from each other with one of said electrode means having contacting engagement with a first body of mercury for said 10 relay. plunger means adapted to be normally supported in iioating relation in said ilrst body of mercury for supporting a second body of mercury in insulated relation with respect to said first body ot mercury and in contacting engagement with the other lof said electrode means, coil means adapted vwhen energized to attract said, plunger means to draw the latter into said rst body of mercury and displace the same into contacting engagement with said second body of mercury to complete a circuit between said pair of electrode means, and said plunger means having metering means between said bodies of mercury for e'tl-i'I fecting a time delay in the contacting of said lgst body of mercury upon displacement of the same with said second body of mercury upon energization of said coil means and with said plunger means in its attracted position, and through which mercury within said plunger means is returned to said rst body of mercury for effecting a time delay in disengaging of said rst body of mercury from said second body of mercury upon de-energlzation of said coil means and with said plunger means in its normal position.

4. A mercury relay comprising a metal casing l for supporting a first body of mercury therein and adapted to serve as one electrode for the relay, an electrode member mounted in insulated relation in said casing and serving as a second electrode for said relay, plunger means open at the upper end thereof disposed in said casing normally in floating relation in said rst body of mercury comprising a metal sleeve member and a member of insulating material disposed internally of said sleeve member having a cupshaped portion for supporting a second body of mercury in insulated relation with respect to said rst body of mercury, and in contacting engagement with said second electrode said cupshaped portion and said metal sleeve member forming a recess therebetween, coil means associated with said casing adapted when energized to attract said plunger means to submerge the latter in said first body of mercury and thereby effect engagement thereof with said second body of mercury through the open upper end of said plunger means providing quick making of a circuit between said electrodes, and said plunger means having metering means in communication with said recess through which mercury within said plunger is returned to the first body of mercury for eiecting a time delay in disengaging of said rst body of mercury from said second body of mercury upon de-energization of said coil means and with said plunger means in its normal position.

5. A mercury relay comprising a metal casing for supporting a iirst body of mercury therein and adapted to serve as one electrode for the relay, an electrode member mounted in insulated relation in said casing and serving as a second electrode for said relay, plunger means disposed in said casing normally infloating relation in said rst body of mercury comprising a metal sleeve member and a member of insulating material disposed internally of said sleeve member having a cupshaped portion for supporting a second body of mercury in insulated relation with respect to said iirst body of mercury and in contacting engagement with said second electrode, ooil means associated with said casing adopted when energized to effect displacement of said first body of mercury into engagement with said second body of mercury to complete a circuit between said electrodes, and said plunger means having metering 1l means between said bodies of mercury for effecting a time delay in the contacting of said first body of mercury with said second body of mercury upon energization of said coil means and with said plunger in attracted position.

6. As an article of manufacture a plunger com prising a 'substantially cylindrical hollow metal sleeve, and a member of insulating material disposed within said metal sleeve and closing one end thereof, said last named member having a hollow cylindrical portion disposed co-axially of the axis of said metal sleeve with the outer cylindrical surface of said last named member being spaced from the inner cylindrical surface of said metal sleeve to define an annular recess open at its upper end therebetween, and metering orifice means for said plunger communicating with said annular recess.

7. As an article of manufacture a plunger comprising a substantially cylindrical hollow metal sleeve, and a member of insulating material disposed within said metal sleeve and closing one end thereof, said last named member having a hollow cylindrical portion disposed co-axially of the axis of said metal sleeve with the outer cylindrical surface of said last named member being spaced from the inner cylindrical surface of said metal sleeve to define an annular recess open at its upper end therebetween, and there being an opening in said metal sleeve member opening into said annular recess.

8. A mercury relay comprising a shell for supporting a main body of extending inwardly of the upper end of said shell, plunger means closed at the lower end thereof and adapted to be normally supported in floating relation in said main body of mercury comprising, an outer vertically extending metal sleeve member open at its upper end, and an inner insulator member having a vertically extending tubular extension open at its upper end and supporting a body of mercury in contact with said electrode member in the normal floating position of said plunger, said tubular extension and said metal sleeve forming a recess therebetween below the upper end of said tubular extension, metering orifice means in said metal sleeve opening into said recess, and coil means adapted when energized to draw said plunger means into said first body of mercury and displace the same so that the level thereof is disposed above the upper end of said tubular extension.

9. A mercury relay, comprising a shell for supporting a main body of mercury, an electrode extending inwardly of upper end of such shell, plunger means closed at the lower end thereof and adapted to be normally supported in floating relation in said main body of mercury comprising, an outer vertically extending metal sleeve member open at its upper end, and an inner insulator mercury, an electrode 4ing a recess therebetween member having a vertically extending tubular extension open at its upper end and supporting a body of mercury in contact with said electrode member in the normal floating position of said plunger, said tubular extension and said metal sleeve forming a recess therebetween below the upper end of said tubular extension, metering orifice means in said metal sleeve opening into said recess, and coil means adapted when energized to attract plunger means and submerge the same in said main body of mercury, said metal sleeve being of a length so that in the attracted position of said plunger means the upper end thereof is disposed below the level of the displaced mercury providing quick making of contact between said nrst and second bodies of mercury.

10. A mercury relay comprising a shell for supporting a main body of mercury, an electrode extending inwardly'of the upper end of said shell, plunger means closed at the lower end thereof and adapted to be normally supported in floating relation in said main body of mercury comprising, an outer vertically extending metal sleeve member open at its upper end, and an insulator member having a vertically extending tubular extension open at its upper end and supporting a body of mercury in contact with said electrode member in the normal floating position of said plunger1 said tubular extension and said metal sleeve formbelow the upper end of said tubular extension, metering orifice means in said metal sleeve opening into said recess, coil means adapted when energized to attract said plunger means and immerse the same in said first body of mercury, said metal sleeve in the attracted position of said plunger means being disposed above the level of the displaced mercury and with the upper end of said tubular extension being dis posed below the level of the displaced mercury, whereby said metering means effects a time delay in the contacting of the displaced first body of mercury with said second body of mercury.

JOHN P. KEATING.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,228,058 Schmidt May 29, 1917 1,786,018 McCabe Dec, 23, 1930 1,915,462 Zuckschwerdt June 27, 1933 2,025,593 King Dec. 24, 1935 2,060,813 Larson Nov. 17, 1936 FOREIGN PATENTS Number Country Date 482,947 Great Britain Apr. 4, 1938 

